25 years ago on April 7 1994 radio stations in Rwanda transmitted a message: It is time to “cut the tall trees” and “eliminate the cockroaches.” It was a signal for Hutu militia to begin the wholesale extermination of their Tutsi neighbors and moderate Hutus.

Over the next 100 days nearly a million people were killed—mostly by machetes and other primitive weapons. Many of the massacres occurred in churches where victims had sought refuge. (Today many of these, displaying remains of the victims, have become memorials.)

That such horror could occur in a strongly Catholic country raised troubling questions. Nuns, priests and catechists were among the victims. (In other cases, shockingly, they collaborated with the killers.) Church leaders were largely mute.

The shame was not confined to the Church. European colonists had propagated the notion that Hutus and Tutsis were separate races and played them against each other. Now, in the midst of systematic genocide, the international community largely stood by and watched.

If there were many perpetrators as well as guilty bystanders, there were also those who showed immense courage in efforts to save others. And among those labeled “cockroaches” there were many who bravely asserted their humanity and died proclaiming the name of God.

Let us not suppose that such a thing could not happen again or could not happen here. It could. It has.

It doesn’t begin with bombs and machetes. It begins with dehumanization of the “other,” with scapegoating, with “They’re not human beings, they’re animals.” The antidote also begins now—in resisting hate, in proclaiming and defending the sacred dignity of all God’s children.